U.S. ZIP +4 Database

Why trust our ZIP+4 Database?

A lot of companies make claims that they are the best but we truly feel no other Zip Code provider provides nearly the quality of data and support as we do. We've been in operation since 2003 and have an extensive customer list of fortune 500 companies, individuals and small businesses. We also answer our phones. Seriously, we do not hide. Call us at 1-800-425-1169. ZIP-Codes.com was the first to offer an unconditional money back guarantee because we know our ZIP Code Database quality is superior. We are not just licensees of the USPS, we work directly with them and they license data back from us. We also work directly with other data vendors such as Pitney Bowes. Quality and service are our #1 priorities. But do not just trust us. See why you should chose us.

Are there parts to a ZIP Code?

Yes, a full ZIP+4 is actually comprised of 5 parts. 12345-6789 for instance may be grouped as [123] [45] [ - ] [67] [89].

1. [123]: The first 3 digits of the ZIP Code are for a Sectional Center (in rural areas) or Large City.
2. [45]: The last 2 digits of the ZIP Code are for the Post Office Facility or Delivery Area.
3. [ - ]: The dash/hyphen is always required and separates the 5 digit ZIP Code from the +4.
4. [67]: First 2 digits of the ZIP+4 are the Sector or Several Blocks.
5. [89]: Last 2 digits of the ZIP+4 are the Segment or One Side of a Street.

Why do ZIP+4 records come in low/high ranges instead of individually?

For most addresses, a single ZIP+4 is the norm. Just 1 ZIP+4 will cover several houses on a block or side of the street. However, large businesses or those receiving a large volume of mail may be given a range of ZIP+4 codes so that they can route mail to specific departments. A range of ZIP+4 codes may also be assigned to a corresponding range of PO Boxes (PO Box 1004 would have ZIP+4 1004), or a single PO Box could have a full range of ZIP+4 codes (PO Box 1004 would have ZIP+4 1000 through 1100).

Because the USPS allows some instances of ZIP+4 ranges, the requirement to display the data in ranges applies to even singular ZIP+4 codes.

Do you have every ZIP+4 in the U.S. listed separately?

Unfortunately, due to the reasons listed above, no. The ZIP+4 data is only available in ranges.

What does ND as the last two characters in a ZIP+4 mean?

ND as the last two characters in a ZIP+4 mean “Non Deliverable”. It simply means that the USPS has this in their system, but does not actively deliver the mail to that address. USPS documentation has this to say about non-deliverable addresses: “Non-deliverable areas are areas to which the USPS does not deliver mail, such as vacant lots and land that borders railroad tracks. Mailers should not match an address identified as a non-delivery area.”

How do you match data from 5-digit database to the ZIP+4 database?

The ZIP+4 database is very large and is missing certain pieces of information such as City. City information can retrieved from the included 5-digit ZIP Code database.

Most people match ZIP+4 to ZIP Code in the 5 digit ZIP Code Database using just the ZIP Code. While this method works, a more precise method of matching is using the Preferred Last Line City State key from the ZIP+4 database and matching this to the City State Key in the 5 digit ZIP Code Database. This will provide the city and state names which are available for this ZIP+4 record. From there, please use the MailingName field to determine if a City Alias is valid for mailing purposes or not.

Urbanization names only exist for records in Puerto Rico. For Puerto Rico ZIP+4 records only, you can obtain the Urbanization City State Key and match this to the City State Key in the 5 digit ZIP Code database. In the matching 5 digit ZIP Code database record, the City Name field will contain the urbanization name. The same process is used to obtain the municipality name.

The city name in the 5 digit ZIP Code Database can contain many types of names: preferred last-line, urbanization, municipality, and other names by which a given 5-digit ZIP Code is known.

Do you have any other formats for the data?

Unfortunately, no. CSV is the most concise and versatile format for transferring the ZIP+4 data from system to system. It is the only data format we provide this information in.

What is from/to latitude and longitude

ZIP+4 records for the most part represent a number of houses, apartments, or businesses along a street. They do not represent singular points. In an attempt to provide more useful information regarding location, a starting point (From Latitude and From Longitude) indicate where a ZIP+4 record begins while the ending point (To Latitude and To Longitude) indicates where it begins. All areas between those two points can be thought of as being part of that ZIP+4.

Unfortunately, not all ZIP+4 codes are straight lines. Many areas curve, bend, and follow streets that are not in a straight line, so some interpretation and understanding of what is physically in between those two points must be taken into account.

References

1. U.S. Postal Service [Last Updated: 5/1/2022], https://www.usps.com
2. U.S. Census, https://www.census.gov
3. ZIP-Codes.com Internal Data Creation [Last Updated: 5/1/2022], https://www.zip-codes.com
4. Precisely [Updated Quarterly], https://www.precisely.com/
5. U.S. Geological Survey [Updated as needed], https://www.usgs.gov/
6. U.S. Census American National Standards Institute (ANSI) [Last Updated: 5/1/2022], https://www.census.gov
7. U.S. Census 2010 [Decennial] [Last Updated: 1/1/2010], https://www.census.gov
8. U.S. Census [Updated Yearly], https://www.census.gov